Division of Infectious Diseases, Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA.
BMC Infect Dis. 2014 Mar 31;14:176. doi: 10.1186/1471-2334-14-176.
KPC-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are associated with high mortality; however, their virulence determinants are not well defined.
We investigated the virulence and plasmid transferability among KPC-containing K. pneumoniae isolates.
KPC-2 and -3 were successfully conjugated and retained by a virulent K2 K. pneumoniae recipient isolate. Antimicrobial susceptibility testing showed KPC-2 and -3 donor strains were resistant to more than four classes of antibiotics while the K2 isolate was only initially resistant to ampicillin. After conjugation of KPC-2 and -3, the K2 K. pneumoniae transconjugants became resistant to all beta-lactams. Additionally, the KPC K2 K. pneumoniae transconjugants continued to retain its high serum resistance and murine lethality.
Conjugation and retainment of KPC by virulent K2 K. pneumoniae and the ability of the tranconjugants to maintain its high serum resistance and murine lethality after conjugation was demonstrated in this study. These findings are concerning for the potential of KPC-like genes to disseminate among virulent K. pneumoniae isolates.
产碳青霉烯酶的耐碳青霉烯类肺炎克雷伯菌（CRKP）感染与高死亡率相关；然而，其毒力决定因素尚未明确。
我们研究了携带 KPC 的肺炎克雷伯菌分离株之间的毒力和质粒可转移性。
KPC-2 和 -3 成功地被一个毒力强的 K2 肺炎克雷伯菌受体分离株接合和保留。药敏试验显示，KPC-2 和 -3 供体菌株对超过四类抗生素具有耐药性，而 K2 分离株仅最初对氨苄西林具有耐药性。KPC-2 和 -3 接合后，K2 肺炎克雷伯菌转导体对所有β-内酰胺类抗生素均产生耐药性。此外，KPC K2 肺炎克雷伯菌转导体继续保持其高血清抗性和小鼠致死性。
本研究证明了毒力强的 K2 肺炎克雷伯菌对 KPC 的接合和保留，以及转导体在接合后仍能保持其高血清抗性和小鼠致死性的能力。这些发现令人担忧，因为 KPC 样基因有可能在毒力强的肺炎克雷伯菌分离株中传播。
